1. Field of the Invention
The present invention relates to answering services in a telephone communication system and, more specifically, to an apparatus and method for providing automatic answering services to a portable telephone unit from a base station unit.
2. Description of the Related Art
In an automatic answering service provided to a portable telephone user, a caller's messages are recorded when the user selects an automatic answering service function and the portable telephone is in a serviceable state. Furthermore, a call may be connected, according to a selection by the user, while the automatic answering service is being provided. This automatic answering service is possible when the call connection is completed. Generally, the automatic answering service is used to receive and record a caller's information when the user does not answer the call. Similarly, upon telephoning the portable telephone with a radio paging receiver, if the portable telephone is in an off-the-hook state, the caller can call the user by an automatic radio paging service or provide a voice message using a voice mail box. If the portable telephone user has a wire telephone, a service for transmitting or transferring the call to that telephone can be provided. However, these services, which are provided by request to the subscriber, are only possible when the portable telephone user has other communication equipment, such as, for example, the radio paging receiver or the wire telephone. In the automatic answering service for the wire telephone, an additional unit is installed to that telephone so that if the telephone is not answered within a predetermined time, a caller's message is recorded. Meanwhile, if the portable telephone is in a non-serviceable area or its power source is turned off, the automatic answering service will not be provided. As a result, the caller may unsuccessfully attempt the call connection several times.
It is to be appreciated that when the caller calls the portable telephone user, if the call is not connected with the portable telephone, the automatic answering service is not provided to the caller. To support the automatic answering service even in such a circumstance, other communication equipment, for example, the radio paging receiver or the wire telephone, is required. However, the automatic answering service received through the wire telephone may result in a restriction on the mobility of the portable telephone user. Thus, since the automatic answering service for the portable telephone is carried out by the called terminal itself (i.e., the portable telephone), a communication channel must be formed with the portable telephone.